Colorado River cutthroat trout conservation strategy for southwest Colorado to reestablish Colorado River cutthroat

49 Pages·1994·2.1 MB·English

by  Langlois, David

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88073783
INTERIM
COLORADO RIVER CUTTHROAT TROUT
CONSERVATION STRATEGY
FOR SOUTHWESTERN COLORADO
SH
167
. C87
C65
1994
BLM Library
Denver Federal Center
Bldg. 50,00-521
PO. Box 25047
Denver, CO 80225
SIGNATURE PAGE
We, the undersigned, enter into this Conservation Strategy to share the benefits derived by acting
cooperatively to protect and enhance populations of Colorado River Cutthroat trout in southwest
Colorado. This is not a financially or legally binding agreement.
l<Jm±
Bob Storch, Forest Supervisor
Grand Mesa, Uncompahgre and Gunnison NFs
Webb, Forest Supervisor l Daje
( San Juan and Rio Grande NF
Alan Kesterke, District Manager
Montrose District, BLM
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COLORADO RIVER CUTTHROAT TROUT
CONSERVATION STRATEGY
FOR SOUTHWEST COLORADO
TO REESTABLISH
COLORADO RIVER CUTTHROAT
PREPARED BY:
David Langlois Michael Japhet
Colorado Division of Wildlife Colorado Division of Wildlife
Montrose, CO Durango, CO
Jeff Cameron Corey Sue Hutchinson
U.S. Forest Service U S. Forest Service
Grand Mesa, Uncompahgre, Gunnison San Juan National Forest
National Forests Durango, CO
David Smith John Castellano
Bureau of Land Management Bureau of Land Management
Gunnison, CO Durango, CO
November, 1994
Additional copies of this report may be obtained from the following public offices:
Colorado Division of Wildlife, 2300 South Townsend Avenue, Montrose, CO 81401
Grand Mesa-Uncompahgre-Gunnison National Forest, 2250 Hwy 50 South, Delta CO 81416
Citation of this report should be:
Langlois, D., J. Cameron, C. S. Hutchinson, M. Japhet, D. Smith, and J. Castellano. 1994.
Colorado River cutthroat trout conservation strategy for southwestern Colorado. Colo.
Div. ofWildl., Montrose, CO and U.S. For. Serv., Delta, CO. 42 pp.
TABLE OF CONTENTS
ADAPTIVE MANAGEMENT. iv
EXECUTIVE SUMMARY.v
INTRODUCTION.1
NATURAL HISTORY .3
Description .3
Historic Range.5
Current Distribution.5
Habitat and Water Quality Requirements.8
Factors Causing the Decline .9
THE CONSERVATION STRATEGY 10
Inventory of Habitat and Populations.10
Reestablish Populations.11
Habitat Improvement and Restoration .13
Protection of Habitat and Populations .15
INFORMATION AND EDUCATION
.16
LITERATURE CITED 17
APPENDICES .20
Appendix A. Potential Cutthroat Waters on USFS Lands.21
Appendix B: Selection Criteria for Streams.25
Appendix C: Selection Criteria for Lakes .32
Appendix D: Protocol For Preparing Fish Specimens in the Field.40
iii
ADAPTIVE MANAGEMENT
The Colorado Division of Wildlife (DOW), U.S. Forest Service (USFS) and Bureau of Land
Management (BLM) developed this Conservation Strategy for Colorado River cutthroat trout.
Experts from universities, organizations and other individuals also reviewed the plan. Agency
personnel used the best written information available to them and collective knowledge,
experience and professional judgment of others in producing this Conservation Strategy. It is
hoped the ideas can be used by all concerned with the Colorado River cutthroat trout to restore
populations of ColoradoRiver cutthroat trout, protect sensitive habitats, and coordinate
conservation activities. Goals and objectives will be attained and funds spent depending on
appropriations, priorities, and other operational constraints.
This Conservation Strategy and its objectives and actions must be responsive to change to be
effective. The document is subject to modification as dictated by new findings in conservation
biology, changes in species status and completion of tasks in the plan. Revisions are the
responsibility of the authors. The Strategy does not necessarily represent the views of all
personnel of the agencies nor official positions or approvals of cooperating agencies,
organizations and individuals. Potentially affected interests in the southwestern Colorado should
view this draft plan as an interactive information document that will aid the decision making
process as various alternatives for recovering Colorado River cutthroat trout are considered.
EXECUTIVE SUMMARY
This Conservation Strategy suggests cooperative efforts by the Southwest Region of the
Colorado Division of Wildlife, the San Juan and Grand Mesa-Uncompahgre-Gunnison National
Forests of the U. S. Forest Service, and Montrose District of the Bureau of Land Management to
preserve Colorado River cutthroat trout (Oncorhynchus clarki pleuriticus). These local
agencies have collaborated in preparation of this Conservation Strategy with the intent to achieve
the following in southwestern Colorado:
1. Reestablish populations of Colorado River cutthroat trout to ensure their long term
survival.
2. Protect key streams and watersheds through management practices that provide
optimum trout habitat.
3. Coordinate management of this trout and its habitat through interagency
conservation efforts.
GOAL: To ensure the long term survival of Colorado River cutthroat trout in southwestern
Colorado. The conceptual idea is to protect the genetic purity and preserve the genetic
variability of remaining stocks of this trout.
OBJECTIVE: Create at least three metapopulations1 of Colorado River cutthroat trout: one
for each of the major river basins that include the Gunnison (Uncompahgre-North Fork), the San
Juan (Piedra-Pine-Navajo-Animas-LaPlata-Mancos), and Dolores (West Fork-San Miguel)
drainages. Ancillary to this work it would be desireable to also manage a number of refugia that
include populations in isolated streams and populations in high lakes that must be maintained by
periodic stocking from genetically acceptable stocks.
ACTIONS: ■ Inventory of habitat and populations - a database of potential
waters and populations, population sampling and monitoring
■ Reestablish populations - identify potential waters, make
transplants, manage wild broodstocks.
■ Habitat improvement and restoration - manage streams and lakes in
selected watersheds to create optimum trout habitat.
■ Protect of habitat and populations - exclude nonnative fishes, set
fishing regulations, improve land management practices.
■ Public information - build consent for Conservation Strategy
elements.
'A metapopulation is a collection of localized smaller populations with some amount of dispersal possible for
individuals to move among populations.
INTRODUCTION
"We are charged with the perpetuation of native species insofar as possible. Historically, most of
the reducton of cutthroat trout habitat area in the higher elevations has been traceable to our own
stocking activities and tose other conservation agencies such as the Forest Service. I refer mainly
to introductions of brook and rainbow into cutthroat waters. I feel it is high time we make a
listing of remainine pure cutthroat waters and set them aside as inviolate native trout
waters regarding stocking " This quotation from Wayne R. Seaman, state fishery manager for
the DOW, was in a memo from the southwest regional manager, C.E. Till, to the hatchery
superintendents and the WCOs. It was dated March 9. 1964!
The cutthroat trout (Oncorhynchus clarki) is the only trout native to Colorado. Four subspecies
have been identified: Colorado River cutthroat trout (O. c. pleuriticus), greenback cutthroat
trout (O. c. stomias), Rio Grande cutthroat trout (O. c. virginalis) and the now extinct yellowfin
cutthroat (O. c. macdonaldi). During the past 100 years, Colorado River cutthroat trout have
been adversely affected by stocking of non-native salmonids and development of land and water
resources. Like many of the native trouts in the American west, the present distribution of the
Colorado River cutthroat trout is a small fraction of what is was historically. As of this writing,
pure Colorado River cutthroat trout in southwestern Colorado exist in only six isolated headwater
tributaries in the San Juan and Gunnison drainages. This subspecies is currently a U. S. Fish and
Wildlife Service Category 2 species (may be appropriate for listing as federally threatened or
endangered), is considered a Species of Special Concern by the DOW, and is on the USFS
regional sensitive species list.
State and Federal agencies are becoming increasingly cognizant of the critical nature of the issues
facing us today in the management of threatened or endangered fish wildlife and sensitive species
populations and their habitat. On January 25, 1994, the Chief of the USFS, Jack Ward Thomas,
signed a Memorandum of Understanding made and entered into by the USFS, BLM, National
Park Service, U. S. Fish & Wildlife Service and National Marine Fisheries Service to establish a
general framework for cooperation and participation in the conservation of species that are
tending toward federal listing under the Endangered Species Act. It is a significant agreement
wherein the agencies agree to work together to achieve a common goal of species conservation
through protection and management of the habitats and ecosystems. Also in 1994, the
International Association of Fish and Game Directors signed an agreement with the federal
agencies to cooperate towards the same end. Implementation of Conservation Strategies such as
this one for Colorado River cutthroat trout will ensure the requirements of federal planning
systems and the National Environmental Policy Act are fulfilled. This Strategy completes
coverage of conservation efforts for the Rocky Mountain region in Colorado. It is an interim
Strategy on a regional level that complements other interagency planning efforts for Colorado
River cutthroat trout. This Strategy is consistent with the USFS plan amendment (pp. Ill 33-34,
Gen. Dir. 01 and 01c).
The USFS and BLM are responsible for managing public land habitats for this subspecies in
southwest Colorado. The Grand Mesa, Uncompahgre and Gunnison National Forests encompass
nearly 3 million acres of land which contain approximately 3,657 miles of perennial streams. The
San Juan National Forest covers nearly 2.7 million acres of land which contain approximately
1,000 miles of perennial stream. The BLM administers 2.1 million acres of land containing
approximately 1,250 miles of streams. In addition to these stream miles, the San Juan National
Forest has 9600 acres of lake, the BLM has 92 acres, and the Grand Mesa-Uncompahgre-
Gunnison National Forest contains approximately 12,000 acres of lake habitat.
The primary mission of the Colorado DOW is protection of fish and wildlife including Colorado
River cutthroat trout populations. This responsibility is mandated by Colorado statutes and
regulations under the authority of the Colorado Wildlife Commission.
2
NATURAL HISTORY
DESCRIPTION
Colorado River cutthroat trout are yellow with a pale to brilliant red band which runs horizontally
along both sides of the body. Males become much more crimson along their ventral region during
spawning. The spotting pattern is variable, depending on geographic locality, but consists of
large, black spots located mostly above the lateral line and posteriorly. It is very infrequent that
spots are present on the head. Behnke and Zam (1976) provided a taxonomic description of
Colorado River cutthroat trout. This subspecies differs from other trouts of the southern Rocky
Mountain basins in its higher scale counts (170-205+ in lateral series, 38-48+ above lateral line).
Pyloric caeca typically number 25 to 45 with averages in the 30 to 40 range. The number of gill
rakers ranges from 17 to 21 and averages 19. Vertebrae number 60 to 63 with mean value
usually 61 or 62.
In 1977, Binns published a rating system to determine the degree of purity of Colorado River
cutthroat trout in Wyoming. The rating system categorized populations into grades of purity
based on degree of suspected hybridization (Table 1). The rating assigned grades from A (most
pure) to F (obvious hybrids) using the range of variability of meristic characters and spotting
pattern.
Table 1. Purity rating criteria used to determine degree of purity of Colorado River cutthroat trout Range
given for scales and pyloric caeca represent mean values. An A represents the most pure populations; an F
the least pure.
Meristic character Grade
and spotting
pattern A B C D F
Scales' 180+ 168-179 155-167 142-154 120-141
Pyloric caeca s40.9 41.0-44.5 44.6-48.5 48.6-53.0 53.1+
Basibranchial teeth* 2 0-10% 10-20% 20-40% 40-75% 75-100%
Spotting pattern3 Uniform, no Slight variability Some variability Quite variable Obvious hybrid
variability yet still yet still spotting
pleuriticus pleuriticus
‘Number of scales two rows above lateral line.
2 Percent of specimens lacking basibranchial teeth.
5 Variability in size, number, shape and position of spots among specimens from the same population.
3